Pluggable connectors have been used for connecting individual transmission lines and for connecting groups of discrete copper wires, twisted pairs, and a few coaxial cable and optical fibers.
The connector arts have not generally kept up with the rapid changes being made in the computer and telecommunication arts, such as in the developments for single and multi-chip modules, thermal conduction modules, silicon chip carriers, and modules on printed circuit cards or boards. The groups of electrical pins used on multi-chip modules have generally operated well at the frequencies previously required. However future direction is to use the higher frequencies and bandwidths, which cannot be handled well by the old groups of pins on a module.
This future trend is indicated by the historical trend in designing digital computer systems with ever increasing processor speeds and performance. This trend derived from complex and costly process technologies in semiconductors and electronic packaging modules. With shrinking lithographic ground rules processed on expensive cameras and etchers, increasingly dense integrated logic circuits were printed on heat-generating bipolar transistors on silicon chips soldered to costly ceramic multilayer modules using water cooling. Typically, several of these modules are connected by thousands of pins inserted into thousands of plated holes in a motherboard to comprise a computer uniprocessor. Performance extensions were achieved by coupling 8 to 12 uniprocessors into a multiprocessor complex (such as a sysplex or cecplex) with significant losses of uniprocessor efficiency and cost-to-performance ratio related to interference in all processors accessing the same main memory.
Connectors are involved in the fabrication of a spectrum of computer assemblies from workstations to supercomputers (including microprocessors loosely coupled into massively parallel systems), which can be constructed by using one or more large CMOS (Complimentary Metal Oxide Semiconductor) chips per processor on an air cooled multichip module, or by these and other types of chips on water cooled thermal conduction modules.
A fundamental problem in maximizing the efficiency of any connector construction is input/output (I/O) bandwidth, processor-to-memory and processor-to-processor, and how its signals are handled in the programmed switching of circuits.
New electronic connector packaging structures are needed to significantly increase the bandwidth and high-frequencies needed for "open systems" interconnectivity between system components of different manufacturers or across product-line families. Open systems architectures require plug compatibility and network interconnections for distributed processing.
Some of these needs may be met by this invention arranging large numbers of miniaturized I/O connectors having broad bandwidth and very high frequency capabilities on complex electronic packages which are the functional building blocks of such future systems.
Flexibility in connection is provided by this invention supporting different types of connectors in large numbers in a matrix, in which any connector may connect either or both of copper and/or optical-fiber transmission lines to a module, and which can offer designers the flexibility of providing any mix of connection types for various arrangement requirements.
In this specification, the term "module" includes several levels of packaging, as follows: A "substrate" is the inner-most part of a module; in the preferred embodiments the substrates are primarily ceramic, silicon or glass-ceramic. A "chip carrier" is a substrate having semiconductor chips placed thereon in a module, and the chip carrier is a higher level of packaging than the substrate. A "housing" is a frame around the chip carrier to seal or protect the chip carrier and is the outer-most part of a module. In the preferred embodiment described herein, the "module" encompasses a substrate, a chip carrier, and a housing, although at times the term module may be used to refer to one of these parts. A module may be referred to as either a single-chip module or multi-chip module (MCM) according to whether its contained chip carrier has single or multiple chips (i.e. a module may contain one or more chips). An example is the commercially-used thermal conduction module (TCM) constructed with alumina substrates, which is a form of MCM. An upper major surface of the TCM is covered with a thermal cooling structure, and the other major surface is covered with conductive I/O (input/output) pins which are used to plug the module into a computer framework. The substrate in a TCM is constructed with many internal layers of wiring to accommodate the interconnections among multiple chips. The TCM has a thin, low profile shape to support internal cooling in the TCM. Direct contact heat sinks are used. The low profile chip carrier in the module having small edge surfaces compared to the top and bottom surfaces of the chip carrier. The module may not have sufficient area on any surface to provide a desired number of conventional pin-in-hole type connectors, and the narrow edges of the TCM do not contain any conductive I/O pins.
Conventional pin-in-hole connectors are subject to noise which limits module performance.